/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.test.util;

import org.springframework.lang.Nullable;
import org.springframework.util.ObjectUtils;

/**
 * JUnit independent assertion class.
 *
 * @author Lukas Krecan
 * @author Arjen Poutsma
 * @since 3.2
 */
public abstract class AssertionErrors {

    /**
     * Fails a test with the given message.
     *
     * @param message describes the reason for the failure
     */
    public static void fail(String message) {
        throw new AssertionError(message);
    }

    /**
     * Fails a test with the given message passing along expected and actual
     * values to be added to the message.
     * <p>For example given:
     * <pre class="code">
     * assertEquals("Response header [" + name + "]", actual, expected);
     * </pre>
     * <p>The resulting message is:
     * <pre class="code">
     * Response header [Accept] expected:&lt;application/json&gt; but was:&lt;text/plain&gt;
     * </pre>
     *
     * @param message  describes the value that failed the match
     * @param expected expected value
     * @param actual   actual value
     */
    public static void fail(String message, @Nullable Object expected, @Nullable Object actual) {
        throw new AssertionError(message + " expected:<" + expected + "> but was:<" + actual + ">");
    }

    /**
     * Assert the given condition is {@code true} and raise an
     * {@link AssertionError} if it is not.
     *
     * @param message   the message
     * @param condition the condition to test for
     */
    public static void assertTrue(String message, boolean condition) {
        if (!condition) {
            fail(message);
        }
    }

    /**
     * Assert two objects are equal and raise an {@link AssertionError} if not.
     * <p>For example:
     * <pre class="code">
     * assertEquals("Response header [" + name + "]", expected, actual);
     * </pre>
     *
     * @param message  describes the value being checked
     * @param expected the expected value
     * @param actual   the actual value
     */
    public static void assertEquals(String message, @Nullable Object expected, @Nullable Object actual) {
        if (!ObjectUtils.nullSafeEquals(expected, actual)) {
            fail(message, ObjectUtils.nullSafeToString(expected), ObjectUtils.nullSafeToString(actual));
        }
    }

    /**
     * Assert two objects are not equal and raise an {@link AssertionError} otherwise.
     * <p>For example:
     * <pre class="code">
     * assertNotEquals("Response header [" + name + "]", expected, actual);
     * </pre>
     *
     * @param message  describes the value being checked
     * @param expected the expected value
     * @param actual   the actual value
     */
    public static void assertNotEquals(String message, @Nullable Object expected, @Nullable Object actual) {
        if (ObjectUtils.nullSafeEquals(expected, actual)) {
            throw new AssertionError(message + " was not expected to be:" +
                    "<" + ObjectUtils.nullSafeToString(actual) + ">");
        }
    }

}
